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  <div class="section" id="future-import-is-not-the-first-non-docstring-statement">
<h1><code class="docutils literal notranslate"><span class="pre">__future__</span></code> import is not the first non-docstring statement<a class="headerlink" href="#future-import-is-not-the-first-non-docstring-statement" title="Permalink to this headline">¶</a></h1>
<p>The <code class="docutils literal notranslate"><span class="pre">__future__</span></code> module enables a module to use functionality that is mandatory in future Python versions. If it was possible to place the <code class="docutils literal notranslate"><span class="pre">__future__</span></code> module in the middle of a module, then that would mean that one half of the module could use the old Python functionality for a given feature, and the other half (after the <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import) could use the new Python functionality of the feature. This could create many strange and hard-to-find bugs, so Python does not allow it.</p>
<div class="section" id="anti-pattern">
<h2>Anti-pattern<a class="headerlink" href="#anti-pattern" title="Permalink to this headline">¶</a></h2>
<p>The code below attempts to place a <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import statement in the middle of the module. When Python encounters the <code class="docutils literal notranslate"><span class="pre">from</span> <span class="pre">__future__</span> <span class="pre">import</span> <span class="pre">division</span></code> statement it raises a <code class="docutils literal notranslate"><span class="pre">SyntaxError</span></code> and halts execution. However, if the code were to execute, the first <code class="docutils literal notranslate"><span class="pre">print</span></code> statement would print out <code class="docutils literal notranslate"><span class="pre">1</span></code> (which is how the division operator behaves in Python versions 2 and below), but the second <code class="docutils literal notranslate"><span class="pre">print</span></code> statement would print out a decimal value, which is how the division operator functions in Python versions 3 and later. As you can see, this could create very strange behavior, so Python does not allow <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import statements in the middle of a module. The module can use either version of the division operator, but it can’t use both.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nb">print</span><span class="p">(</span><span class="mi">8</span> <span class="o">/</span> <span class="mi">7</span><span class="p">)</span>  <span class="c1"># 1</span>

<span class="c1"># SyntaxError</span>
<span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">division</span>

<span class="c1"># 1.1428571428571428</span>
<span class="nb">print</span><span class="p">(</span><span class="mi">8</span> <span class="o">/</span> <span class="mi">7</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="best-practice">
<h2>Best practice<a class="headerlink" href="#best-practice" title="Permalink to this headline">¶</a></h2>
<div class="section" id="remove-future-import">
<h3>Remove <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import<a class="headerlink" href="#remove-future-import" title="Permalink to this headline">¶</a></h3>
<p>In the modified code below, the author decides that the module needs to use the old functionality of the division operator. The only solution in this case is to remove the <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import statement from the module.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># removed __future__ import statement</span>
<span class="nb">print</span><span class="p">(</span><span class="mi">8</span> <span class="o">/</span> <span class="mi">7</span><span class="p">)</span>  <span class="c1"># 1</span>
</pre></div>
</div>
</div>
<div class="section" id="place-future-import-before-all-other-statements">
<h3>Place <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import before all other statements<a class="headerlink" href="#place-future-import-before-all-other-statements" title="Permalink to this headline">¶</a></h3>
<p>In the modified code below, the author decides that the module needs the new functionality of the division operator. The only solution then is to place the <code class="docutils literal notranslate"><span class="pre">__future__</span></code> import statement at the beginning of the module</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">division</span>

<span class="c1"># 1.1428571428571428</span>
<span class="nb">print</span><span class="p">(</span><span class="mi">8</span> <span class="o">/</span> <span class="mi">7</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
<div class="section" id="references">
<h2>References<a class="headerlink" href="#references" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li><p>PyLint - W0410, misplaced-future</p></li>
<li><p><a class="reference external" href="http://simeonvisser.com/posts/how-does-from-future-import-work-in-python.html">Simeon Visser - How does ‘from __future__ import …’ work?</a></p></li>
<li><p><a class="reference external" href="https://docs.python.org/2/library/__future__.html">Python Standard Library - __future__</a></p></li>
</ul>
</div>
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